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Introduction and testing of an alternative control approach for a robotic prosthetic arm.

Griggs L, Fahimi F - Open Biomed Eng J (2014)

Bottom Line: An experimental 4DOF robotic arm was used as the platform for testing the proposed control approach.The two control methodologies, joint control and Cartesian control, were tested on five able-bodied human subjects.Improvement of one control methodology over the other was measured by the time it took for the subjects to complete a simple motor task.

View Article: PubMed Central - PubMed

Affiliation: Mechanical & Aerospace Engineering University of Alabama in Huntsville, Huntsville, 35899 Alabama, USA.

ABSTRACT
Commercially available robotic prosthetic arms currently use independent joint control. An alternative controller involving only control of the hand in a Cartesian frame rather than controlling each joint independently is proposed and tested. An experimental 4DOF robotic arm was used as the platform for testing the proposed control approach. As opposed to joint control, Cartesian control requires the solution to the inverse kinematics problem. The inverse kinematics solution was developed for the robotic arm using the extended Jacobian method. The two control methodologies, joint control and Cartesian control, were tested on five able-bodied human subjects. Improvement of one control methodology over the other was measured by the time it took for the subjects to complete a simple motor task. The timed trial results indicated that Cartesian control was both more intuitive and more effective than joint control. So, the results suggest that much improvement can be achieved by using the proposed Cartesian control methodology.

No MeSH data available.


Related in: MedlinePlus

AX-12 Smart Arm Denavit-Hartenberg link frameassignment [16]. z 's are the unit vectors point along the joint's axisof rotation. x 's are the unit vectors pointing to the orientation ofthe next frame.
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Figure 6: AX-12 Smart Arm Denavit-Hartenberg link frameassignment [16]. z 's are the unit vectors point along the joint's axisof rotation. x 's are the unit vectors pointing to the orientation ofthe next frame.

Mentions: The frames that are affixed to the AX-12 Smart Arm are shown in Fig. (6). Frame 0 is attached to the patient's body. Frames 1 to 4 are attached to links 1 to 4, respectively. Frame 5, which is considered the tool frame, is also attached to link 4 (the gripper, or the hand). However, its origin is located at the center of the gripper (the hand). The Denavit-Hartenberg (DH) parameters of the assigned frames are listed in Table 1. Using the DH parameters, one can find the 3×3 rotation matrices that map any vector expressed in an upper frame to a lower frame i-1. Such rotation matrices are noted by ,Rii−1where i=1,...,5 (see [16]).


Introduction and testing of an alternative control approach for a robotic prosthetic arm.

Griggs L, Fahimi F - Open Biomed Eng J (2014)

AX-12 Smart Arm Denavit-Hartenberg link frameassignment [16]. z 's are the unit vectors point along the joint's axisof rotation. x 's are the unit vectors pointing to the orientation ofthe next frame.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231378&req=5

Figure 6: AX-12 Smart Arm Denavit-Hartenberg link frameassignment [16]. z 's are the unit vectors point along the joint's axisof rotation. x 's are the unit vectors pointing to the orientation ofthe next frame.
Mentions: The frames that are affixed to the AX-12 Smart Arm are shown in Fig. (6). Frame 0 is attached to the patient's body. Frames 1 to 4 are attached to links 1 to 4, respectively. Frame 5, which is considered the tool frame, is also attached to link 4 (the gripper, or the hand). However, its origin is located at the center of the gripper (the hand). The Denavit-Hartenberg (DH) parameters of the assigned frames are listed in Table 1. Using the DH parameters, one can find the 3×3 rotation matrices that map any vector expressed in an upper frame to a lower frame i-1. Such rotation matrices are noted by ,Rii−1where i=1,...,5 (see [16]).

Bottom Line: An experimental 4DOF robotic arm was used as the platform for testing the proposed control approach.The two control methodologies, joint control and Cartesian control, were tested on five able-bodied human subjects.Improvement of one control methodology over the other was measured by the time it took for the subjects to complete a simple motor task.

View Article: PubMed Central - PubMed

Affiliation: Mechanical & Aerospace Engineering University of Alabama in Huntsville, Huntsville, 35899 Alabama, USA.

ABSTRACT
Commercially available robotic prosthetic arms currently use independent joint control. An alternative controller involving only control of the hand in a Cartesian frame rather than controlling each joint independently is proposed and tested. An experimental 4DOF robotic arm was used as the platform for testing the proposed control approach. As opposed to joint control, Cartesian control requires the solution to the inverse kinematics problem. The inverse kinematics solution was developed for the robotic arm using the extended Jacobian method. The two control methodologies, joint control and Cartesian control, were tested on five able-bodied human subjects. Improvement of one control methodology over the other was measured by the time it took for the subjects to complete a simple motor task. The timed trial results indicated that Cartesian control was both more intuitive and more effective than joint control. So, the results suggest that much improvement can be achieved by using the proposed Cartesian control methodology.

No MeSH data available.


Related in: MedlinePlus